1. Field of the Invention
The present invention generally relates to laboratory containers and more specifically concerns biological culture system containers.
2. Prior Art
In laboratory work it is often necessary to provide a sealed container for culturing specimens which permit a laboratorian to selectively control the container environment to suit the growth and development needs of any of a variety of microorganisms.
For example, in clinical microbiology it is often necessary to utilize a sealed container providing a controlled environment for supporting growth of certain anaerobic microorganisms. For this purpose, the prior art has provided sealed containers which, in combination with a variety of hydrogen and carbon dioxide generators, will attain and maintain anaerobic conditions. The basic principle involved here is the reaction of suitable chemical reagents, in the presence of a catalyst, to generate hydrogen gas and carbon dioxide gas in a sealed container into which the culture samples have been previously inserted. The generated hydrogen in the presence of the catalyst combines with the molecular oxygen in the sealed container to form water condensate and thus, as the oxygen combines with the hydrogen in the container it is replaced by carbon dioxide to provide an anaerobic condition. The prior art further teaches the use of chemical indicators, such as methylene blue, to indicate the presence or absence of an environment characteristic of anaerobic conditions.
A variety of prior art devices have been utilized as culture system containers. Generally, a culture system container is a device for receiving and containing a plurality of individual culture samples and for providing controlled environmental conditions during development of the individual cultures. The containers have generally been sized to accommodate a plurality of culture samples, in standard circular or rectangular culture-type dishes. For example, one such container is an elongated cylindrical container diametrically sized to accommodate the standard circular-type dishes in a stacked arrangement. The axial dimensions of the container in this type of prior art device is such that it will accommodate up to a dozen or more stacked culture dishes. The anaerobic conditions in this type of device are produced by a hydrogen and carbon dioxide generator as discussed above, or by external sources of carbon dioxide gas pumped through vents or ports in the cap, or heated helium, of the system container. There are, however, significant problems with this type of device. For example, where there are multiple culture samples included in the container and the clinician or laboratorian wants to evaluate a particular sample, he must open the container, remove the particular sample, and reseal the container. The anaerobic conditions must then be regenerated. The problems with this procedure are several. With particularly obligate anaerobic microorganisms, the result is a possible arrest in development or delayed development because of the interrupted anaerobic conditions. Another significant problem arises when the system container is of the type which must be connected to an external source of carbon dioxide gas. In this situation the container is, for all practical purposes, immobile and thus all culture samples must be carried to the container from wherever they are taken. This results in inconvenience and delay.
Another prior art device utilizes a "plastic-glove" type container for maintaining anaerobic growth conditions. This device has been utilized in a variety of specific forms but generally includes a pliable plastic bag-like container into which the culture samples are inserted along with a carbon dioxide generator. Again there are significant problems with this type of prior art container. Storage and handling difficulties are encountered with "plastic-glove" containers. Further, where a number of different samples are included in a single container the entire system must be breached each time the researcher wishes to remove a particular sample. Again, with certain glove-type containers the anaerobic conditions must be regenerated each time the container is opened to remove and inspect a sample.
For additional discussion of this and other prior art devices, see: J. E. Rosenblatt and P. R. Stewart, Anaerobic Bag Culture Method, Journal of Clinical Microbiology, p. 527 (June, 1975); I. Jerome Abramson, A Mobile Unit To Facilitate Isolation of Anaerobic and Aerobic Microorganisms, American Laboratory, p. 69 (October, 1973); and J. H. Brewer and D. L. Allgeier, Safe Self-Contained Carbon Dioxide-Hydrogen Anaerobic System, Applied Microbiology, P. 985 (November, 1966).
The present invention provides a far improved culture system container which eliminates problems experienced by the prior art and provides additional features and advantages. The present invention includes a generally circular tray having an upstanding circular wall with a removable sealing top. The top and bottom of the tray are generally transparent. The container or tray is sized to accommodate several standard culture-type dishes lying in a side by side arrangement on the bottom of the tray. In addition, the trays are conveniently stackable. The advantages here are significant. Each tray contains several culture dishes of a single sample, and the system can remain closed until conclusion of the anaerobic development. Another advantage is achieved by placing the samples side by side in the container rather than stacking them one upon the other. Here the researcher can view the development of the individual microorganisms through the transparent top without having to open the container. Another advantage is that the individual containers are stackable to provide convenient handling and storage. Further advantages of the present invention will become apparent upon consideration of the drawings and the description herein.